Outcomes of protracted bacterial bronchitis in children: A 5-year prospective cohort study.

Background And Objective: Long-term data on children with PBB has been identified as a research priority. We describe the 5-year outcomes for children with PBB to ascertain the presence of chronic respiratory disease (bronchiectasis, recurrent PBB and asthma) and identify the risk factors for these.

Methods: Prospective cohort study was undertaken at the Queensland Children's Hospital, Brisbane, Australia, of 166 children with PBB and 28 controls (undergoing bronchoscopy for symptoms other than chronic wet cough). Monitoring was by monthly contact via research staff. Clinical review, spirometry and CT chest were performed as clinically indicated.

Results: A total of 194 children were included in the analysis. Median duration of follow-up was 59 months (IQR: 50-71 months) post-index PBB episode, 67.5% had ongoing symptoms and 9.6% had bronchiectasis. Significant predictors of bronchiectasis were recurrent PBB in year 1 of follow-up (OR = 9.6, 95% CI: 1.8-50.1) and the presence of Haemophilus influenzae in the BAL (OR = 5.1, 95% CI: 1.4-19.1). Clinician-diagnosed asthma at final follow-up was present in 27.1% of children with PBB. A significant BDR (FEV improvement >12%) was obtained in 63.5% of the children who underwent reversibility testing. Positive allergen-specific IgE (OR = 14.8, 95% CI: 2.2-100.8) at baseline and bronchomalacia (OR = 5.9, 95% CI: 1.2-29.7) were significant predictors of asthma diagnosis. Spirometry parameters were in the normal range.

Conclusion: As a significant proportion of children with PBB have ongoing symptoms at 5 years, and outcomes include bronchiectasis and asthma, they should be carefully followed up clinically. Defining biomarkers, endotypes and mechanistic studies elucidating the different outcomes are now required.